Smoke detector with transmitter and receiver in housing inserted in ceiling, to emit beam for reflection off smoke

摘要

Detector has transmitter (2) and receiver (3), each with covering (5,7). Covering allows beam (6) through from transmitter and reflected beam (8). When smoke (1) occurs in monitored area, beam emitted from transmitter is reflected on smoke and measured by receiver. Intensity of reflection indicates density of smoke and distance of smoke from device is detected from angle of incidence.